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Possible Severe Wx in The Desert Southwest?

Posted: Thu May 29, 2003 11:08 am
by MonsoonDude
ISOLATED SEVERE storms could fire up in the Desert Southwest, and Mountains of Southern California...If you look at this map it looks at 500MB the winds are from the southeast and stay that way through 850MB, which is closer to the ground of course.
Image

Now look at the 1000MB map..The winds are now out of the Northwest...
Image

now correct meif I am wrong, but we have winds changing direction with height,so doesn't that mean possible Isolated Supercells?

Ok, well i off.going to do some storm chasing the the Eastern Deserts Today of California Today, and Friday.

Kev

We Might See

Posted: Thu May 29, 2003 2:15 pm
by Aslkahuna
some high based microburst type severes here but in looking at the cloud cover we are getting right now, I don't think the moisture is quite up there enough to give us big boomers. Additionally, although there is shear the actual shear vectors and associated velocities aren't all that great. The 1000 mb level is close to the surface in the deserts and that NW wind is the typical NW wind that blows frm PHX to TUS every day.

Steve

Posted: Thu May 29, 2003 2:35 pm
by Arizwx
VAD Wind profiles have been consistant now for 72hrs+ for an increase in POPs for Trstrms over the Mountains from the Whites down thru E Maricopa Co..Pinal Co,possibly Reddington Pass and the Santa Ritas.
The H2O ground values are so dry,that although we have a current DP of 52F(near late June levels),the nocturnal radiational cooling is retarded as PM temps stay hot albeit the precursur Clr Skies exist,a CAP is now in place as it were,, a Thermal Low off to our WSW by 240km and daily afternoon/eve hot winds fm the SSE to 34 the SFC is dry as prohibition.Expect some dry LTG,Virga and some CBs that MAY slide into the Canelo/Nogales Hills area S of Rio Rico on the AZ/MX border Fri Sat Sun.
DJ

The TUS Sounding

Posted: Thu May 29, 2003 4:05 pm
by Aslkahuna
was an Inverted V type sounding this morning and since I expect most of the moisture increase to occur at the mid levels, I would suspect that an unstable Inverted V will result with the chance for dry high basers with microburst type activity and the attendant blowing dust. The convergence line south of Vicente's Line is showing activity as seen on the 1km visual imagery and this could be a factor tonight for areas in far SE AZ. The line is associated with confluence between the ULL off of Baja and the UH to our north. As part of the ULL ejects ahead of an approaching system in NoCA, we could see some action this weekend with dry SW flow setting up thereafter.

Steve

Re: The TUS Sounding

Posted: Thu May 29, 2003 4:45 pm
by Arizwx
Aslkahuna wrote:was an Inverted V type sounding this morning and since I expect most of the moisture increase to occur at the mid levels, I would suspect that an unstable Inverted V will result with the chance for dry high basers with microburst type activity and the attendant blowing dust. The convergence line south of Vicente's Line is showing activity as seen on the 1km visual imagery and this could be a factor tonight for areas in far SE AZ. The line is associated with confluence between the ULL off of Baja and the UH to our north. As part of the ULL ejects ahead of an approaching system in NoCA, we could see some action this weekend with dry SW flow setting up thereafter.

Steve


Interestingly,the local Wx is setting up much as per our discussion..however..lest I eat a crow..its a good 24-30hrs early.The RAD SSW of SV and SW of DUG clearly showed a small plume of latent moisture in the Mid Levels explodeing along the SW edge of the Utah/Colo ULL..Hmmm.Then the influence of the ejecting Baja Lo ...a Thermal Lo near Calexico,CA/Imperial Valley and even some influence from a SoWest/Cent,TX HI AND a deep Offshore Pacific Trough way out in the Tuna Lanes well off of Diego by 400nm.No real dry slot as indicated,rather the inverted V as you aptly see.If the notch grows a Nose in S/C AZ,trailing latent CBoomers Could refire near SV to Nogales/Rio Rico.If it arches its back..we could have a Nasty Outflow boundry with LTG/Dust.
Visuals out the 'Hotel California' Portholes indeed verifies the pre discussed.Nice CB forming near Vail/North and Mod Levels juicing to 50F Dew/slack winds and a modified lower current of only 99F.
The Mexican Sierra Madre looks real healthy this PM,as spinal flow is on the correct vector with the E migrating 4 corners Hi.
Latest PHX Sounding have Helicity/Cape Values jumping from this AMs 483
JKG to a VERY respectable progged 1128!Lift indices getting a rework...poss Neg7.Bring it! 8-) Shear evident.Problem is,I see the 4km IR loop with summary of Neg Temos Upstairs showing very cold,unstable environment.Neg 30C and lower,may mean Hailers.Isentropic and Orographic Lift mechanism nealry in place.This is getting exiting now..

Posted: Thu May 29, 2003 4:55 pm
by Rainband
Enjoy the storms and be safe guys!!! :wink:

Posted: Thu May 29, 2003 5:23 pm
by Arizwx
Latest obs out of Sierra Vista indicates:Trstrm in progress 85F/wind SE 6/DP NA
kahuna's LTG Detectors should be reeling in Data and Chirping.Nice Iso Cell just SSW of SV past 20min.

TUC 98F/Pty Cdy/wind N 6 DP 48F

Those Cold Cloud Tops are squeezing every bit of PW out..Isolated Hailer is possibilty.More incoming for SV accrording to KEMX 88D.Unstable air is evident.
Tonights' POPS for TUS up to 30%.

BEEEEP-BEEEEP-BEEEEP-BEEEEP

Posted: Thu May 29, 2003 6:34 pm
by Aslkahuna
BZZZZZZZZT: THE NATIONAL WEATHER SERVICE IS TUCSON ARIZONA HAS ISSUED A SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN COCHISE COUNTY INCLUDING THE TOWNS OF SIERRA VISTA, HUACHUCA CITY AND FORT HUACHUCA. AT 4:00 PM MST TUCSON DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 8 MILES SOUTHEAST OF SIERRA VISTA MOVING NORTHWEST AT 20MPH. DAMAGING WINDS AND BLOWING DUST MAY ACCOMPANY THIS STORM. MOTORISTS IN THE WARNING AREA SHOULD BE AWARE OF THE POSSIBILITY OF HEAVY RAIN AND SUDDEN CHANGES IN VISIBILITY. THE STORM IS EXPECTED TO BE IN THE FOLLOWING LOCATIONS AT THE FOLLOWING TIMES

SIERRA VISTA 4:15 PM

HUACHUCA CITY 4:25 PM

At the present time, we are experiencing moderate to heavy rain with frequent CG lightning and loud thunder. Winds have not been strong here but the velocity data from the TUS radar indicated 50 knots associated with a high based outflow passing just north of Sierra Vista which we confirmed visually. Thunderstorms are associated with a convergence line ahead of the ULL which has shifted inland across Baja and appears to be lifting out adding rotational dynamics to the mix (which is probably why my son observed a funnel cloud on his way to SV). Important to note that this is not a monsoon pattern since the flow below the ULL is SW and not SE.

Steve

BEEP BEEP BEEP ------- tone -----------------

Posted: Fri May 30, 2003 10:44 pm
by M2
DUST STORM WARNING
Thanks Steve & DJ for providing the outflow boundary that blasted us
again in Phoenix this evening with massive dust and big wind :D

We've had several dust storm warnings but storms are now dissipating,
but oh what a mess it makes...trees down last night.

...It IS fun practice though...for the You-Know-What.... :Fade-color

Currently @ 8:45pm MST: Temp/90 DP/52 BP/29.78 RH/26% Wind/25Gusting41 Visibility/5miles (if you're lucky)